Ztherapy excitement

Well I am over the top excited to be getting a set of 4 screw SU's done by Ztherapy! I kept my current set of carbs on the car as to have a good set to baseline all my readings, then I can get the new SU's on start tuning.

I know the quality of the products put out by ZT, I am looking forward to getting them on, but any advice and things I should do first. Also any helpful advice on pitfalls in removing the intake?

I'll be interested in hearing other peoples tips and tricks for this also, I have a set of carbs/intake manifold out getting polished and look forward to putting them on. It look really straight forward unless a stud breaks...

If the manifold is already off, you've already been through the toughest IMO. The exhaust bolts, and intake/exhaust studs are the main things I was worried about. I let the penetrating oil soak in a while before I tried cracking anything loose. I bought the stud kit from MSA. Studs for the intake manifold made installation much easier.

My '73 had coolant through the manifold so I used a 1/2" pipe plug in the thermostat housing and a plug on the T before the cooling line is routed behind the head (passenger side)

I don't know if this made a difference but I didn't tighten the balance tube completely when I re installed the manifold. My thinking was that the manifolds would install flat against the head

My main suggestion is do not use a "header" gasket. The paper ones suck. Use a Nissan or other foil and graphite manifold gasket.

For the other guy, use a long extension with a U-joint and socket. You'll have to get in some fairly uncomfortable positions and there will likely be a little pain along with stuffing your hands in tight spaces. It's not that big a deal though.

Hi Jon, have you had bad experience with the MSA intake/exhaust gasket? If I understand you, you're referring to a paper style like you might see from Mr Gasket
just as a quick side note, I finally bought my Energy poly bushings so everything is in place to do the coil overs... just need time. I'll send you a picture when I do finally install everything.

As far as the u-joint and socket, I agree. I believe it was the 2nd or 3rd cylinder that has a stud that is impossible to reach with a normal socket. It was even a pain with a shallow universal. Getting the stock manifold unstuck from the head took some convincing with a pry bar. Just take your time.

If you're referring to the POS gasket that comes with their 6-1 header, yes I had problems with it. I actually bought the header from Arizona Z Car, but it's the same header, and yeah, I drove the car once and it cracked. Never had any trouble with a graphite gasket.

If you're referring to the POS gasket that comes with their 6-1 header, yes I had problems with it. I actually bought the header from Arizona Z Car, but it's the same header, and yeah, I drove the car once and it cracked. Never had any trouble with a graphite gasket.

I should have taken a picture of mine. The msa gaskets I used on my car were not a simple paper gasket, more like a sandwhich of paper and foil in the middle. I doubled them up, gluing them together with copper RTV, then glued the header to the gasket. Got everything mounted, then snug, then I torqued in stages. I let the rtv dry a good half hour before doing the last torquing.

My header leak is fixed, with the header simply resting on the studs, the 2nd primary was too low to seal so with a little tweaking of that primary and keeping the header lifted, everything sealed. Keep in mind this is a who-knows-how-old Clifford header and one of the previous owners cut the flange between the primaries.

Just get ready to spend a lot of time freshening up everything under the hood.
the ZT carbs look SOOOO damn good, it'll make everything else look shabby by comparison.
big difference in idle and smoothness of engine, and my original carbs ran pretty well.

That was quick. I didn't realize they could do them that fast. I'll be sending mine off at some point. In the past I've resisted because I didn't want the car not drivable for a period of time but the sad reality is that I just haven't driven it in months anyhow.

I had a spare intake and carbs I used as a core. My current carbs which work pretty good are still on the car. I will take some vacuum readings and use my uni-syn on it before I remove them to see what difference these carbs make. Also, would like to know how off sync my current set of carbs are. Actually, I think they are pretty good. But to have a working baseline is always good to have.

Make sure before you install them that the small little fuel delivery hoses at the bottom of the carbs aren't kinked. One of mine must have gotten budged during shipping, so I had to take the clamp off and reposition it. The video and paperwork tells you all of this though.

yup, it is the 630 dollar core, plus the intake and balance tube polishing. I also picked up a new PVC valve and PVC hose to the crankcase. OH and got a unisyn while I was at it. Cannot wait to get the PB blaster on the bolts and get that intake/exhaust off.

Is that what a polished intake manifold and balance tube are supposed to look like? Huh, I've been polishing mine and they're sort of looking like the attached, wonder what I'm doing wrong?? Honestly, your new carbs look amazing. I've been seriously considering sending my polished stuff off to Bruce for final assembly and tuning. I'm sure he will do a much better job then I ever could... I look forward to hearing about how your final installation turns out.

Yours are definitely more polished than mine buddy! Great job. I would highly recommend clear coating those to prevent tarnish after your done. So much work should be protected.

I think the word polish in Z therapy speak is more of a tumble - polish - clean. I think you have taken it to the extreme...I am sure Bruce has experimented with the best polish he can offer to his clients and still make money. Obviously he could not do what your doing to yours and charge so little.

Just to freshen up this topic, our carb pieces are run through a high impact machine polish which is designed to close up the cell structure of the aluminum replicating the finish when new. It is not our intention to change the look of the product by doing a chrome polish. We'll leave chrome polish to the owners.

Hi Bruce, I think we all know that you don't aim for a chrome level polish (I was just kidding around). Your product is beautiful, and as you said, returns your clients to [as new or better than new]. Which is appropriate.

Every time I see your work product, my first thought is "wow".

Smoothing and polishing until you have no more fingerprints isn't nor should it be your goal. (and it will never be my goal again).

As I mentioned earlier, if your willing, I'd like my set-up to end up in your expert hands to assemble (now that you have shipped me everything to do it, I'm hoping to ship it all back ).

Hi Bruce, I think we all know that you don't aim for a chrome level polish (I was just kidding around). Your product is beautiful, and as you said, returns your clients to [as new or better than new]. Which is appropriate.

Every time I see your work product, my first thought is "wow".

Smoothing and polishing until you have no more fingerprints isn't nor should it be your goal. (and it will never be my goal again).

As I mentioned earlier, if your willing, I'd like my set-up to end up in your expert hands to assemble (now that you have shipped me everything to do it, I'm hoping to ship it all back ).

Sometimes my responses may come off sounding too obvious but I find myself thinking in terms of "who may be reading this that may not be as up to speed on our services" as you the "learned" ones.

Call me and we can work out the particulars. For enough money, etc etc etc

Hey that looks really good - but they must have shorted you one man. Three is what you need I tell you .

Like the 3 and manifold I have still setting in the box from when we looked at them. You rs will be on soon and a lot faster than mine - like all of your Z projects vs mine. Yep I am further behind !

Congrats on those again - now get them on and lets go pull some ZX parts off !

Yeah, triples would have been sweet bud. But I am pretty sure I could not have pried them out of your hands with a 5 foot crow bar! haha. I like the ease of running the SU's, and I know I will never make more power than they can supply. Unlike you who plan to build a monster

the Z Therapy carbs were probably the best money I ever spent on my car

Agreed. I went from being afraid everytime I drove my car for fear of a breakdown to total confidence and enjoyment. Not to overstate things; but they are the single reason I started driving my car again.

I'm not familiar with the term 3-screw or 4-screw SU's. What does that mean, and how do I know what I have. I have 2 sets, one on my new '70 Z, and another from a '72 Z, on my parts car '73.
Also, I'd be interested to know if you guys prefer to run separate air cleaners on the carbs, or if the original cleaner housing (big orange cover) is used more often?

The 3 or 4 screw deal is merely the number of screws holding the dome on. Your 70 carbs are more than likely 4 screw and the 72 carbs are 3 screw. At least that's what they would have been from the factory.

The factory air cleaner is a fine, very functional piece of gear. It has good air horns built in, both carbs draw from a common air cource and cooler supply air can be had through the "snorkle" from forward of the engine heat.

I'm not familiar with the term 3-screw or 4-screw SU's. What does that mean, and how do I know what I have. I have 2 sets, one on my new '70 Z, and another from a '72 Z, on my parts car '73.

Also, I'd be interested to know if you guys prefer to run separate air cleaners on the carbs, or if the original cleaner housing (big orange cover) is used more often?

3- or 4-screw refers to the number of screws holding the domes in place.

Whatever air cleaner you run, you should use the air horns that the original air cleaner came with. I'm gonna fabricate a new intake, using a K & N cone filter and aluminum tubing to an aluminum air cleaner I'm making this Winter. I'm cutting the air horns out of my OEM air cleaner to incorporate into the new design. The air horns "smooth out" the flow of air into the carbs. Better air flow = more power.

Thanks for that info. The '70 does have the 4 screw carbs and the '72 carbs are 3 screw carbs.

And, I didn't even realize it until I just went out and looked, the parts car doesn't have the air horn cover. Basically, the previous owner took the cover off, but left the backing plate on, and then the OEM air filter is there, covered by a piece of flat aluminium in the same shape as the air filter. Not sure why that is...oh well.

Z therapy Carbs

Sometimes my responses may come off sounding too obvious but I find myself thinking in terms of "who may be reading this that may not be as up to speed on our services" as you the "learned" ones.

Call me and we can work out the particulars. For enough money, etc etc etc

You have done my 4 screw carbs as well as my friend's 3 screw carbs. They are excellent! As matter of fact, it is way better than factory ones. I have rebuilt so many of them, but none of them turn out as good as yours. Especially your throttle shaft with roller bearings. My car idles smooth like an injected car.
I strongly recommend your SU set up to everyone!

UPDATE: Today I got a baseline reading on my currently installed factory carbs. There is no telling how many times these have been messed with, but I slapped my new edlebrock sync tool I got from Bruce on there at idle with the engine warm and the carbs are FAR from balanced. ONe shot the red cup up to almost the 4th line. The back carb only managed to barely move it to the first. Since I am going to take these off, and they do run what I thought was well. I am looking forward VERY much to seeing how well she will run with a balanced set of carbs on there.

PS. I adjusted the fast idle screw up to 3000 rpm per the SU video and the readings were far more even. But the front carb was still reading higher. I think I may have a vacuum leak in the back carb somewhere. Still all bolts are currently sitting in penetrating fluid, so the removal will start soon. My new intake/exhaust studs have arrived, as have my new air cleaner decals, filter, and my orange paint is on order. I have my new MSA intake/exhaust gasket waiting installation.

Fun times ahead.

Just if your curious. I adjusted the mixture nut on the bottom of the carb on the rear carb to see if I could get it to come in to match the front, and it had no effect. I think I recall that is how you adjust them at idle. I will have to watch the SU video again. Its wonderful by the way!

Zedyone_kenobi, I am just a few steps ahead of you in the overhaul of the intake and exhaust with ZT carbs. The final upgrade will be replacing the intake with a polished intake, with ZT Euro Tube and replace the stock manifold with Jim Cook 3 to 2 headers. I am still debating if I should cap off the water/coolant line running through the intake manifold. Here in So Cal, we don't get the bone chilling weather that warrants the intake to be pre-warmed by the coolant going through the manifold.

Today it was a dismantling day. The PB-Blaster week of soaking on those rusted bolts really did the job in loosening up the bolts = "no broken bolts". Easily and gently unscrewed the bolts from the heads and they all came off without a hitch. Installed the new intake/exhaust bolt & nut kit from MSA with plenty of the high-temp anti-seize stuff. Also removed, along with all those twisted smog air hoses, is the boat anchor of an air pump and bracket. Taking the smog pump and bracket took more effort then removing the intake and exhaust due to the tight spaces and the zillions of air tubes cluttering the back of the pump. I ran out of time to undo the rusted 2.5 inch pipes and muffler, it'll be next weekend's job along with installing the headers, intake manifold (assuming it will be delivered before the weekend). More adventure to come.

Good Luck on it! I was fortunate as somebody has already beaten me to removing the smog pump. I already have a header, so it sounds like they saved me a ton of work! I think what I may do is try do a photo documentary on this. It will give step by step directions to future Z a holics. Plus as a bonus, it will allow me to track my progress so I can get back to where I was if I forget where something went.

One of my concern in replacing the stock iron exhaust manifold with a uninsulated header is the increase of heat that may effect the carburation. Did you encounter any issue with excessive heat on your setup, assuming your header is not insulated?

One of my concern in replacing the stock iron exhaust manifold with a uninsulated header is the increase of heat that may effect the carburation. Did you encounter any issue with excessive heat on your setup, assuming your header is not insulated?

I'm sure you already know this, but a heat shield could be fabricated really easily. A ceramic coated header with a heat shield would be the best combinaton; probably cooler than the factory setup.

My header was Jet Hot coated, not sure how long ago, and I run the factory heat shield. I am going to send the heat shield off to be powercoated with a high temp coating. I was even thinking of doing a reflective barrier on the back of the heat shield, Think McLaren F1 supercar. Of course I would not use 24 karat gold, but I could find something that has good insulating properties.

Hi Steve, I've had an MSA 6-2 header in my '73 for about 3 years now. It is not coated with anything and not wrapped with anything. I've never had an issue with too much heat under the hood. I've got round top SU's and the stock heat shield.

UPDATE: Due to the amazing great weather we had yesterday I spent the morning removing my intake to prepare for the installation. Everything went very straight forward for the most part. I spilled more coolant that I would have liked, but that was only a 10 minute diversion. THe hardest part of this by far was removal of the studs. Two gave me grief, the others came out rather nicely with using the old two nut method. I also soaked most of them with liquid wrench the day before, which may or may not have helped. I think having a header instead of a stock exhaust manifold gave me more clearance to work as well. ON to the pics...

First pic is my box that I used to keep track of my studs and where they came from. I usually use a piece of cardboard as it is nice to make notes on as you go.

THe next pic recalls something that was said earlier on this post. Gasket differences. The lower gasket is the one off the car. Obviously not a stock one. Notice the metal contact surfaces for the header to rest against. This is like the ultra high quality gaskets I use to use when I rebuild V8's. Above is the meager-by-comparison MSA gasket. I think I want to find another gasket like the one below.

Here is the engine so far. All the studs removed, no casualties yet. I have been using scotch bright to clean up the surface of the header and head. It feels very smooth, and I think will seal quite well.

Here is the old intake and carbs. You can also see the new intake/exhaust stud kit ready to go back in...

THats all for now. ONe question though. I have read some posts on other car forums that its horrible to use antisieze on studs/bolts/spark plugs for aluminum heads. This goes against everything I have ever done. Does anybody have any more insight to this. MY dad is a retired A&P mechanic, and says they use antisieze on aluminum heads all the time.

MOre updates to follow. I have to start sanding my heat shield for refinishing.

THats all for now. ONe question though. I have read some posts on other car forums that its horrible to use antisieze on studs/bolts/spark plugs for aluminum heads. This goes against everything I have ever done. Does anybody have any more insight to this. MY dad is a retired A&P mechanic, and says they use antisieze on aluminum heads all the time.

MOre updates to follow. I have to start sanding my heat shield for refinishing.

Wherever you read that info.......if it was the general consensus of the participants...........stay FAR FAR away from that forum.

I'm excited too! Just ordered the $630 dollar treatment from Bruce at Ztherapy yesterday, plus smooth and polish the intake and balance tube. I actually spent the extra money to have the european style balance tube. I've been working on my 240 for over a year now and am very close to being able to drive it. Bruce said about ten days for him to get the stuff ready and another 3 to 5 days for shipping, I can hardly wait. I'll post pics of the Euro balance tube when I get it

I have always used anti sieze. If anything, I've heard it's more important to use on aluminum for dissimilar metals (ie spark plugs in the head, steel studs in the head, etc). Aluminum on aluminum can gall/tear as well (like stainless).

I pulled the lugs off my Civic to rotate the tires, and the studs had a dab of anti sieze on the threads. Good stuff

Heres what my set-up looks like before it has been run. Those pretty carbs would look great next to a ceramic(shiny header). Be advised, I was told by a friend and verified thru research that you don't want to dial in new carbs with a freshly coated ceramic header. A bad fuel mixture will dull the finish of the ceramic and never come back. I wish I could get some Z therapy carbs, but my carbs are almost new-plus I got some mikunis for after break in.
Good luck with your carbs!

These are the essentially unchanged directions since I had the Sanderson's on my Camaro. It's true, the finish will dull and the coating cracked on my headers. It has more to do with a Mallory distributor with a bad advance curve. High egt's from too much advance really damaged the coating on my headers.http://www.sandersonheaders.com/tech...stallation.php
They have a quick section on new engines and fresh rebuilds. It also says to be careful after performance mods so a drastic enough change can affect exhaust temps

I did an afternoon restore on my Clifford headers using high temp VHT black header paint. I prepped with naval jelly and a good cleaning (the paint is self priming). I have actually been pleasantly surprised by how durable the finish is. I've had a couple clumsy moments with my wrenches and the paint didn't chip

Okay, I got a small case of the while I was at its, and took off the thermostat hosing and the upper radiator hose. I ordered all new seals and hoses, since, you know, I was there. Now here was an adventure. The bolt was so corroded into the thermostat housing the head snapped right off. OH JOY!

Three hours later and some delicate tapping with a rubber mallet I got the housing to loosen it's death grip on the sheared bolt. Now with only 1/4" of bolt sticking out of the head, I had to say my prayers to the good Lord above, said a few to Budda and Allah, just in case they were car nuts too, never hurts to be thorough, and clamped a vice grip to the last remaining threads to see if the bolt would unscrew.

You know many things go through your mind when you attempt something like this. You have this feeling like you know there is a smarter way to do this, but at this point your caveman instincts from the Pre Cambrian period surface and you just want to pick up the car and throw it.

Long story not so long, the bolt nicely unscrewed. Thank the Lord. OR Allah, Or Budda, hell I even thanked my wife.

Kept cleaning things up, put some new paint on the thermostat housing and the heat shield, and started to do some final thread cleaning on the heads.

One question folks. I asked Ztherapy to block of the water passages from the intake. So the water line that does form the thermostat housing to the intake, I assume I can just plug. Also, I should be able to remove the line running around the back of the engine as well. Is this correct. From the looks of it, the coolant does not need this flow path to function correctly.

Any thoughts.

I have to go see if Black Dragon or MSA sells bolts for the Thermostat housing now.

The bolt was so corroded into the thermostat housing the head snapped right off. OH JOY!

Three hours later and some delicate tapping with a rubber mallet I got the housing to loosen it's death grip on the sheared bolt. Now with only 1/4" of bolt sticking out of the head, I had to say my prayers to the good Lord above, said a few to Budda and Allah, just in case they were car nuts too, never hurts to be thorough, and clamped a vice grip to the last remaining threads to see if the bolt would unscrew.

Long story not so long, the bolt nicely unscrewed. Thank the Lord. OR Allah, Or Budda, hell I even thanked my wife.

Actually, that appears to be a common problem. I had the exact same thing happen when I changed the thermostat on my car. What happens is that the shaft of the bolt corrodes and swells in the t-stat housing, so much so that the bolt won't turn and the head breaks off. Once you persuade the housing to give up its death grip on the corroded bolt, my experience has also been that the broken bolts unthread easily. In my case, I had a brand new t-stat housing waiting on the shelf, so I wasn't worried about destroying the one that was stuck.

Short version - new t-stat housings are still available new from Nissan, and are actually rather affordable. I'd recommend having one on hand before attempting to remove a long-attached one.

Oh yeah, ALWAYS thank your wife. It's a good habit to get into.

Originally Posted by Zedyone_kenobi

One question folks. I asked Ztherapy to block of the water passages from the intake. So the water line that does form the thermostat housing to the intake, I assume I can just plug. Also, I should be able to remove the line running around the back of the engine as well. Is this correct. From the looks of it, the coolant does not need this flow path to function correctly.

Correct. Plug it at the t-stat housing, remove the pipe going around the rear of the engine, and cap off the supply to that pipe at the T-fitting on the side of the block.

Correct. Plug it at the t-stat housing, remove the pipe going around the rear of the engine, and cap off the supply to that pipe at the T-fitting on the side of the block.

This is exactly how I did mine, as well.

Here are a few pics that might help you.

Heater hose coolant paths.

Plugged t-stat housing. I forgot what exact plug this was, but I'm pretty sure it was a normal pipe thread (NPT) threaded plug.

You'll need a 3/4" to 5/8" heater hose adapter (splice) to neck down from the larger hose coming from the lower radiator hose outlet assembly to the smaller hose needed at the heater core inlet. All parts stores should have these in stock.

I chose to throw the heater hose T away, along with the metal line assembly and thermostat that snaked around the back of the head.

I used a 1/2" pipe plug in the thermostat housing IIRC. It's an allen head plug (socket head plug?) so it sits flush in the housing. I capped the heater T on the passenger side and completely removed the tubing routed behind the head. It's much cleaner without all the extra cooling lines.

That's good information about the thermostat housing, I'll keep that in mind if/when I need to change the t-stat

THat confirms what I thought. Good info. I was going to order a new T-stat housing Arne, but thought I could save this one with a wire wheel and lots of scrubbing. So far so good. I am prepping it for paint right now. I still need to clean the holes. I am guessing I should liberally coat the next bolt with some copper grease or antisieze before installation. Something to prevent corrosion! YUCK.

Today my orange paint from Classic Datsun showed up, as well as my new tensioner pulley for the AC. All I have left to do is clean out the threads, and I should be able to start putting things back together!

Just need some thermostat housing bolts that go into the head. Must be metric bolt store around clear lake somewhere!

The Ace hardware here in town has a good selection of metric fasteners now. It allowed me to mount my ducted spook with metric bolts. If they are nearby it might be worth a look. I'm not sure on the length since I've never removed the factor thermostat housing bolts

Just curious to see how many of you installed the ZTherapy carbs, strait out of the box, and got it running without tweeking the settings? I know that every application is different and requires some adjustments after installation but just wondering if the car fired up without any adjustments.

Just curious to see how many of you installed the ZTherapy carbs, strait out of the box, and got it running without tweeking the settings? I know that every application is different and requires some adjustments after installation but just wondering if the car fired up without any adjustments.

Mine did. Of course, you can double check the settings on the carbs within a minute by reading the instructions that come with them, and it will fire right up.

While I didn't need the ztherapy treatment, a good pair of carbs will fire right away (once the bowls have fuel). I would verify base settings but base settings should get you going. Synching will be needed on any new set of carbs.

After fighting a pair of leaky carbs, a nicely sealed set is so nice. Air leaks around the throttle shafts will have you pulling out your hair guaranteed.

Just curious to see how many of you installed the ZTherapy carbs, strait out of the box, and got it running without tweeking the settings? I know that every application is different and requires some adjustments after installation but just wondering if the car fired up without any adjustments.

Bolted my new ZTherapy's up, and it started right up (once I got a timing issue straightened out). One quick adjustment with the Uni-sys for high rpm balance, and they've been set ever since.

YOu guys are making me VERY happy! I am about to start bolting parts back up. I am holding off for two reasons. I am thinking that I may want to get some parts cad plated. I have a small pile of connectors and bolts and nuts. I cleaned them up with a wire wheel and Dremel, and they look clean and new, but would look better with a shiny CAD plate.

I also nearly finished up my air cleaner resto yesterday. I have a few runs I need to work out with some 2000 grit and polish off. I think I am going to clear coat the thing when I am done to protect the new stickers I got for her.

All I am waiting on now is gaskets for my Thermostat housing and I am off to the races!

Should be fun. I think I will go ahead and flush the rad while I am here and replace all the hoses. I have to plug up the intake water path anyway.

Okay, today was a great day. I got the header back on as well as the new carbs. They look very purrrrdy. refinished my thermostat housing and cover and got those in. Found some spiffy cad covered grade 8 bolts to install there.

On note of warning. Put the washer and nut loosely on the lower studs for the intake first. Trying to fish those lower nuts on with the header and intake on was a bit of a pain. Apparently I have bear claw hands, and they would not reach very easily. But after many trys and finally MacGeyvering with a wrench and some tape, I got them on. Tomorrow I have to torque all the bolts and then I can start installing my new fuel lines and reroute my coolant lines to take into consideration the lack of intake water passages. MOre to come.

Since you're in Houston, I wouldn't bother with re-attaching the coolant lines. The lines are really to improve warm-up, not cooling, and I assume warming up in Houston is no problem. It just looks so much cleaner without them.

Latest issue is the upper and lower radiator hoses. My factory radiator was upgraded from a two core to a three core. While this is great and all, the outlet and inlet to the radiator seems to be larger than the stock 240Z radiator. I ordered an upper and lower radiator hose from Black DRagon and the part that attaches to the engine is perfect, but the part that had to go onto the radiator was a ultra tight fit. I think its far too tight. I need to find a larger diameter tube hose, with the same bend.

I've heard that ZT has some kind of performance enhancement that they can do on your SU's for extra $$. Does anyone know about this, or has had it done? Interested in understanding the difference between that and a normal overhaul.

They do put in different needles that run more rich. I am not sure that it is part of the basic Ztherapy SS treatment, but I requested them.

I get the impression that the performance in the SU's is mostly due to the correct needle selection and the weight of the oil in the piston. You can control how fast it rises and how much fuel comes out. Until you reach the max CFM the SU's can flow with the pistons fully up, I think you can tune to just about any reasonable performance level.

I used a 1/2" pipe plug in the thermostat housing IIRC. It's an allen head plug (socket head plug?) so it sits flush in the housing.

I went out and measured the threads and on my '72 it is definitely a 1/4" British Std Tapered Pipe Thread so you would want a 1/4" BSP plug, yes? Outer diameter of a 1/4" BSP is just over 1/2". Main thing is not to use a 1/4" NPT plug which has a different thread per inch count.

I went out and measured the threads and on my '72 it is definitely a 1/4" British Std Tapered Pipe Thread so you would want a 1/4" BSP plug, yes? Outer diameter of a 1/4" BSP is just over 1/2". Main thing is not to use a 1/4" NPT plug which has a different thread per inch count.

On my '73 I am pretty certain my thermostat housing is 1/2" pipe (or similar, and definitely way to big to be 1/4 NPT). Reason being I removed a pipe plug from a junk LT1 water pump and it threaded into my housing by hand until taper prevented further tightening. I went "sweet!", wrapped the plug with teflon tape, restarted the plug by hand, and tightened.

In my experience, a different TPI would not allow for tightening by hand or anything else. It's been installed and sealed since I did the header in early September. Maybe something subtle changed in 73? I really don't know, I'm feeling like I got away with a ghetto fix

Thinking a little more, did the 72's have EGR? The water lines on the 73 go to both the EGR and intake manifold. Maybe they changed to 1/2 NPT to allow for more volume/flow

UPDATE:
All parts are on the car. I did not get around to finally torquing the bolts. There is no way I will be able to get a torque wrench on the bolts below the intake, so I will have to use the force.

This is shaping up well. I still have some cleaning to do on the block and run new fuel lines. Still have not figured out how I want to rerun the coolant lines. MOre on that after Turkey day I guess.

The couple hard-to-get-to nuts I had to use a 1/4 drive universal on an extension. Obviously not ideal with a torque wrench but it was the only way to truly control how tight the nuts were. I actually used an inch-pound torque wrench that was 1/4 drive. I understand not everyone has access to an inch-pound torque wrench but it was much easier than a larger torque wrench

I can understand you had to put the carbs on to see how they look but it will be much easier to torque everything with those removed.

On my '73 I am pretty certain my thermostat housing is 1/2" pipe (or similar, and definitely way to big to be 1/4 NPT). Reason being I removed a pipe plug from a junk LT1 water pump and it threaded into my housing by hand until taper prevented further tightening. I went "sweet!", wrapped the plug with teflon tape, restarted the plug by hand, and tightened.

I bought several plugs yesterday. I know one fit very nicely, threaded in with no issues at all. I will see which one it was. I think it may have been NPT.

As far as the carbs go. They were installed by Ztherapy on the manifold when it arrived. I just bolted it up. I may have to remove the carbs to get a good torque on the nuts. I think a 12mm crows foot would help dramatically as well.

Quick note. It seems I made a bit of a mistake when putting my thermostat back on. The spark plug wire holder that bolts to the rear most bolt on the thermostat cover is made of plastic, and when I put it back on, I sort of snapped the plastic in half. Does anybody know who may have an extra?

On my '73 I am pretty certain my thermostat housing is 1/2" pipe (or similar, and definitely way to big to be 1/4 NPT). Reason being I removed a pipe plug from a junk LT1 water pump and it threaded into my housing by hand until taper prevented further tightening. I went "sweet!", wrapped the plug with teflon tape, restarted the plug by hand, and tightened.

Looks like we have different housings!

Looking further at the film, it would make sense to increase the ID of the plumbing to deal with the fact that downstream your Z is supplying the EGR and the Carb while mine is only doing the carb. Having a NPT thread is a real plus as you can install a standard 1/2" NPT thermostat switch for an electric fan.

Quick note. It seems I made a bit of a mistake when putting my thermostat back on. The spark plug wire holder that bolts to the rear most bolt on the thermostat cover is made of plastic, and when I put it back on, I sort of snapped the plastic in half. Does anybody know who may have an extra?

Part 33, Nissan number 22472-E3000, still available from Nissan for around a buck and a half. Same price roughly from MSA. #12-4181.

Ordered my new wire holder today, and since its just plain silly to just order something for $1.53, I had to add a new european curved dizzy. I am hoping my current pertronix will bolt into the new dizzy.

Ordered my new wire holder today, and since its just plain silly to just order something for $1.53, I had to add a new european curved dizzy. I am hoping my current pertronix will bolt into the new dizzy.

The non-emissions 240Z unit. The points dizzy factory installed on 240Zs where emissions controls were not needed. Could be used on a 280Z, but you'd need a 240Z dizzy support pedestal plus Pertronix or suchlike.

We will find out Arne. I have always thought my advance mechanism may be a bit dirty. I will tear it down and clean it after I get the new one in. Should be plug and play for the most part. This will complete my tune up so to speak. After I get the carbs in and balanced, will swap out distributors. I only wanted to change one thing at a time. Carbs alone are a big change, and I expect great things from the Ztherapy units.

Just so you guys know, it is possible to buy just the throttle bodies from Ztherapy. This means that you have to swap all the other parts off your existing carbs, but you'll have brand new throttle shafts, which are the parts that tend to wear out.

I did this on my roadster, and it only ran around $270.00 (with exchange) instead of $630.00. The carbs on my new z appear pretty tight, (though not exactly clean), but I will absolutely use Z therapy againif I need carb work done.

UPDATE:
Not much to report, wife has had me painting the dining room and den this weekend. I did manage to get the radiator empty and got my coolant hoses removed from the spark plug side of the engine. I need to come up with a way to reroute the coolant hose straight to the heater core, versus around the engine to the intake. I need to connect two lines with different diameters. Should not be too hard.

In the mean time, I spent some time polishing my valve cover and refinishing my fuel line so it does not look so 'dirty' next to my purdy carbs. Engine is coming together nicely for now, just slowly.

Installed the carbs with the euro tube this weekend per the ZTherapy instruction and vid. and the idle is about 2k rpm. Adjusted the idle screw on the carbs to close the butterfly valve to lower the rpm and it didn't lower the rpm. I am thinking it could be a vacuum leak somewhere in the intake. If it is a vacuum leak, what's the best way to isolate the leak?

Installed the carbs with the euro tube this weekend per the ZTherapy instruction and vid. and the idle is about 2k rpm. Adjusted the idle screw on the carbs to close the butterfly valve to lower the rpm and it didn't lower the rpm. I am thinking it could be a vacuum leak somewhere in the intake. If it is a vacuum leak, what's the best way to isolate the leak?

Grab a can of brake cleaner, carb cleaner, or similar product from a parts store. Crank the car and let it idle while you slowly spray the product aroudn the intake, vacuum hoses, balance tube, or anything else that could possibly leak. When the idle raises, you've found your leak.

I only suggest doing this if your intake and everything is bare metal still. No clue what brake cleaner would do to hot paint or other coatings.

Installed the carbs with the euro tube this weekend per the ZTherapy instruction and vid. and the idle is about 2k rpm. Adjusted the idle screw on the carbs to close the butterfly valve to lower the rpm and it didn't lower the rpm. I am thinking it could be a vacuum leak somewhere in the intake. If it is a vacuum leak, what's the best way to isolate the leak?

Also make sure your throttle return springs are in the correct spot. I swear I look but I have done it twice where I put the spring for the front carb on the idle-up arm.... not a good spot for it.

Also make sure the linkage tie rod is not keeping your throttle open (balance tube to center linkage). Maybe pop off one of the ends and make sure.

Aside from a good visual, the vacuum leaks are another good place to look. I have had good luck with carb clean. Everything is connected properly? Brake booster hose, balance tube tight, etc

work is on hold for a few days. Still working on the dining room and office paint jobs, but managed to squeeze some Z time in. I found out I have had non functioning choke cables. I can barely get them to move. Not sure how they worked in my older setup. So I will need to get those off and try to lubricate them.

Second, upon trying to start the car (which did roar to life rather quickly, but briefly) I noticed my fuel lines from the bowl to the car were SPEWING fuel on the ground. It was not from the where the jet nozzle is on the body, as that completely dry. Upon closer inspection, when I moved the fuel hose, fuel shot out of a small slit.

I will contact ZT today and see if I can get some replacements. He mentioned in his video that at times those get damaged during shipping. It is easy to see why.

As for how I fixed my coolant. I wanted to reuse the stock fitting that bolted to the side of the block. So I found a heater core cap that was made to block off coolant. It was remarkable easy and I was able to keep the stock routing of my heater hose. On the plus side, and another advantage to the 'while I am here' syndrome. I was able to finally add my heater grommet to the firewall, as well as my new choke cable grommet.

Lets here it for unplanned and extra work.

So, cliff notes version.... I got my carbs hooked up and all lines hooked up and got to hear some fire for a brief second before I saw some fuel leaking.

New fuel lines and new choke cables (or repairing my old ones) and I will be back on the road.

UPDATE:
I wanted to reuse the stock fitting that bolted to the side of the block. So I found a heater core cap that was made to block off coolant. It was remarkable easy and I was able to keep the stock routing of my heater hose.

Hi Stephen.
I've been following this thread with great interest, hoping to largely duplicate your efforts in the near future. Will you provide more details about the heater core cap? Where you purchased it, part no. (if any), etc.

yup, got it at Advanced auto parts. Its just look like a hose with a domed closed end on it.
I will try to see if I kept the package. If not, It would be my pleasure to shoot a close up pic of it for you sir.

Disconnect the choke cables - push the chokes completely off by hand - to make sure the cables aren't holding the chokes on.

FWIW,
Carl B.

This has my vote for the most likely problem. I personally fought with the choke cable setting over and over until I got it right. If the choke is partially engaged you can't actually set the mixture, and it will idle fast.

A vacuum leak makes fuel injected cars idle fast, but I am not sure what would happen with SUs. My bet is that it would just run lean, or not at all.

Found an OEM choke cable assembly on Ebay, and managed to win it for a reasonable sum, and the kind folks at ZT said they would be happy to send me new fuel lines. I cannot stress enough how fantastic it is to deal with people who care about their customers and strive to give them a good product and service.